A thermodynamic theory of the Soret effect in a multicomponent liquid

摘要

A phenomenological theory of the Soret effect in a multicomponent mixture is presented. The theory is applicable to mixtures in which the Soret effect is determined mainly by the energetic interaction between the molecules, such as liquids and dense gases, and it is based on the assumption that the steady state has a maximum number of possible microstates. The equations derived for the separation enable the thermal diffusion factor agr;Tof each component to be calculated using only an equation of state for the mixture and the standard state enthalpy. With a sufficiently accurate equation of state, the calculated agr;Tvalues correspond well with the data on measured agr;Tvalues of liquids and dense gases and show a better correspondence than Haasersquo;s theory. The method presented may be applicable to other coupled transport phenomena in the steady state.